Refactor Tomlib::Dumper to be a littel faster and generate squashed n…

…ested tables

CHANGELOG.md

@@ -1,5 +1,15 @@
 ## [0.2.0] - [unreleased]
 
+- Refactor Tomlib::Dumper to be a littel faster and generate squashed nested tables
+  ```
+  e.g. instead of this:
+  [a]
+  [a.b]
+  [a.b.c]
+
+  the output will be this:
+  [a.b.c]
+  ```
 - Add mention about compliance and passed tests in README.
 - Declare global variables with `rb_global_variable`.
 It may prevent VM from crashing in some cases.

README.md

@@ -118,10 +118,10 @@ Tomlib.dump(hash, indent: false)
 
 ## Performance
 
-`Tomlib` parsing is ~300x faster than `toml-rb` and ~15x faster than `Tomlrb`
-for usual use case (~5KB TOML document size).
+`Tomlib` parsing is ~300x faster than `toml-rb`, ~15x faster than `Tomlrb`
+and ~3x faster than `perfect_toml` for usual use case (~5KB TOML document size).
 
-Generating TOML document is about 1.7x faster than `toml-rb`.
+Generating TOML document is about 2x faster than `toml-rb`.
 
 For full comparison take a look at
 [benchmarks](https://github.com/kgiszczak/tomlib/tree/master/benchmarks)

benchmarks/README.md

@@ -32,9 +32,10 @@ and run benchmarks:
 
 ### Generating (i/s)
 
-Note - Tomlrb gem doesn't support generating TOML documents.
+Note - Tomlrb gem doesn't support generating TOML documents
+and perfect_toml doesn't work under Ruby 3.
 
 |gem|small.toml|default.toml|big.toml|
 |---|----------|------------|--------|
-|Tomlib|137.698k|4.741k|22.785|
-|toml-rb|64.312k (2.14x slower)|2.672k (1.77x slower)|0.129 (175.98x slower)
+|Tomlib|133.456k|5.615k|23.105|
+|toml-rb|65.968k (2.02x slower)|2.695k (2.08x slower)|0.146 (158.59x slower)

lib/tomlib.rb

@@ -42,6 +42,6 @@ module Tomlib
   #
   # @api public
   def self.dump(hash, indent: true)
-    Dumper.new.dump(hash, use_indent: indent)
+    Dumper.new(indent).dump(hash)
   end
 end

lib/tomlib/dumper.rb

@@ -27,52 +27,73 @@ class Dumper
     # @api private
     NAN = 'nan'.freeze
 
+    def initialize(use_indent = true)
+      @use_indent = use_indent
+    end
+
+    # Generate TOML string from ruby Hash
+    #
+    # @param [Hash] hash
+    #
+    # @return [String]
+    #
+    # @api private
+    def dump(hash)
+      result = dump_hash(hash)
+
+      result[0] = '' if result[0] == "\n"
+
+      result
+    end
+
+    private
+
     # Generate TOML string from ruby Hash
     #
     # @param [Hash] hash
     # @param [String, nil] base_key
-    # @param [String] indent
-    # @param [true, false] use_indent
+    # @param [Integer] indent_level
     #
     # @return [String]
     #
     # @api private
-    def dump(hash, base_key = nil, indent = '', use_indent: true)
+    def dump_hash(hash, base_key = nil, indent_level = 0)
       header = ''
       footer = ''
 
       hash.each do |key, value|
         toml_key = to_toml_key(key)
 
         if value.is_a?(Hash)
+          skip = !value.empty? && value.values.all? { |e| e.is_a?(Hash) }
           compound_key = to_toml_compound_key(base_key, toml_key)
-          next_indent = use_indent && base_key ? indent + INDENT : indent
 
-          footer << "\n".freeze << next_indent << '['.freeze << compound_key << "]\n".freeze
-          footer << dump(value, compound_key, next_indent, use_indent: use_indent)
+          unless skip
+            indent = @use_indent ? INDENT * indent_level : ''.freeze
+            footer << "\n".freeze << indent << '['.freeze << compound_key << "]\n".freeze
+          end
+
+          footer << dump_hash(value, compound_key, skip ? indent_level : indent_level + 1)
         elsif value.is_a?(Array) && value.all? { |e| e.is_a?(Hash) }
           compound_key = to_toml_compound_key(base_key, toml_key)
-          next_indent = use_indent && base_key ? indent + INDENT : indent
+          indent = @use_indent ? INDENT * indent_level : ''.freeze
 
           value.each do |el|
-            footer << "\n".freeze << next_indent << '[['.freeze << compound_key << "]]\n".freeze
-            footer << dump(el, compound_key, next_indent, use_indent: use_indent)
+            footer << "\n".freeze <<  indent << '[['.freeze << compound_key << "]]\n".freeze
+            footer << dump_hash(el, compound_key, indent_level + 1)
           end
         else
+          indent = @use_indent ? INDENT * (indent_level > 0 ? indent_level - 1 : 0) : ''.freeze
           header << indent << toml_key << ' = '.freeze << to_toml_value(value) << "\n".freeze
         end
       end
 
-      footer.gsub!(/\A\n/, ''.freeze) if header.empty?
       header << footer
     end
 
-    private
-
     # Generate TOML key from Hash key
     #
     # @param [String] key
-    # @param [true, false] use_indent
     #
     # @return [String]
     #

spec/examples/dumper/array/nested-inline-table.toml

@@ -1,2 +1,3 @@
 [[a]]
+
 [a.b]

spec/examples/dumper/implicit-and-explicit-after.toml

@@ -1,6 +1,5 @@
 [a]
 better = 43
 
-[a.b]
 [a.b.c]
 answer = 42

spec/examples/dumper/implicit-and-explicit-before.toml

@@ -1,6 +1,5 @@
 [a]
 better = 43
 
-[a.b]
 [a.b.c]
 answer = 42

spec/examples/dumper/implicit-groups.toml

@@ -1,4 +1,2 @@
-[a]
-[a.b]
 [a.b.c]
 answer = 42

spec/examples/dumper/inline-table/empty.toml

@@ -18,5 +18,4 @@ not_empty = 1
 
 [[many_empty]]
 
-[nested_empty]
 [nested_empty.empty]

spec/examples/dumper/inline-table/key-dotted.toml

@@ -1,66 +1,43 @@
-[a]
 [a.a]
 b = 1
 
 [[arr]]
-[arr.T]
+
 [arr.T.a]
 b = 1
 
-[arr.t]
 [arr.t.a]
 b = 1
 
 [[arr]]
-[arr.T]
+
 [arr.T.a]
 b = 2
 
-[arr.t]
 [arr.t.a]
 b = 2
 
-[b]
 [b.a]
 b = 1
 
-[c]
 [c.a]
 b = 1
 
-[d]
 [d.a]
 b = 1
 
-[e]
 [e.a]
 b = 1
 
-[inline]
 [inline.a]
 b = 42
 
-[many]
-[many.dots]
-[many.dots.here]
-[many.dots.here.dot]
-[many.dots.here.dot.dot]
-[many.dots.here.dot.dot.dot]
-[many.dots.here.dot.dot.dot.a]
 [many.dots.here.dot.dot.dot.a.b]
 c = 1
 d = 2
 
-[tbl]
-[tbl.a]
-[tbl.a.b]
-[tbl.a.b.c]
 [tbl.a.b.c.d]
 e = 1
 
-[tbl.x]
-[tbl.x.a]
-[tbl.x.a.b]
-[tbl.x.a.b.c]
 [tbl.x.a.b.c.d]
 e = 1

spec/examples/dumper/inline-table/nest.toml

@@ -3,16 +3,16 @@ arr_arr_tbl_val = [ [ { one = 1 } ] ]
 arr_arr_tbls = [ [ { one = 1 }, { two = 2 } ] ]
 
 [[arr_tbl_tbl]]
+
 [arr_tbl_tbl.tbl]
 one = 1
 
 [tbl_arr_tbl]
+
 [[tbl_arr_tbl.arr_tbl]]
 one = 1
 
-[tbl_tbl_empty]
 [tbl_tbl_empty.tbl_0]
 
-[tbl_tbl_val]
 [tbl_tbl_val.tbl_1]
 one = 1

spec/examples/dumper/key/dotted.toml

@@ -1,18 +1,15 @@
-[a]
-[a.few]
-[a.few.dots]
 [a.few.dots.polka]
 dance-with = "Dot"
 dot = "again?"
 
 [[arr]]
-[arr.a]
+
 [arr.a.b]
 c = 1
 d = 2
 
 [[arr]]
-[arr.a]
+
 [arr.a.b]
 c = 3
 d = 4
@@ -31,18 +28,12 @@ j = 10
 k = 11
 l = 12
 
-[many]
-[many.dots]
-[many.dots.here]
-[many.dots.here.dot]
 [many.dots.here.dot.dot]
 dot = 42
 
 [name]
 first = "Arthur"
 last = "Dent"
 
-[tbl]
-[tbl.a]
 [tbl.a.b]
 c = 42.666

spec/examples/dumper/key/escapes.toml

@@ -5,7 +5,6 @@
 ["\"quoted\""]
 quote = true
 
-["a.b"]
 ["a.b"."À"]
 
 ["backsp\b\b"]

spec/examples/dumper/key/quoted-dots.toml

@@ -5,7 +5,6 @@ plain = 1
 plain = 3
 "with.dot" = 4
 
-[table]
 [table.withdot]
 "key.with.dots" = 6
 plain = 5

spec/examples/dumper/new-lines/all.toml

@@ -0,0 +1,19 @@
+foo = "foo"
+bar = "bar"
+
+[a]
+
+[b]
+foo = "foo"
+
+[c]
+
+[[d]]
+
+[[d]]
+
+[[e]]
+
+[[f]]
+foo = "foo"
+bar = "bar"

spec/examples/dumper/new-lines/all.yaml

@@ -0,0 +1,14 @@
+foo: 'foo'
+bar: 'bar'
+a: {}
+b:
+  foo: 'foo'
+c: {}
+d:
+  - {}
+  - {}
+e:
+  - {}
+f:
+  - foo: 'foo'
+    bar: 'bar'

spec/examples/dumper/new-lines/arrays-only.toml

@@ -0,0 +1,9 @@
+[[a]]
+
+[[a]]
+
+[[b]]
+
+[[c]]
+foo = "foo"
+bar = "bar"

spec/examples/dumper/new-lines/arrays-only.yaml

@@ -0,0 +1,10 @@
+a:
+  - {}
+  - {}
+
+b:
+  - {}
+
+c:
+  - foo: 'foo'
+    bar: 'bar'

spec/examples/dumper/new-lines/empty.yaml

@@ -0,0 +1 @@
+{}

spec/examples/dumper/new-lines/keys-and-arrays.toml

@@ -0,0 +1,12 @@
+foo = "foo"
+bar = "bar"
+
+[[a]]
+
+[[a]]
+
+[[b]]
+
+[[c]]
+foo = "foo"
+bar = "bar"

spec/examples/dumper/new-lines/keys-and-arrays.yaml

@@ -0,0 +1,10 @@
+foo: 'foo'
+bar: 'bar'
+a:
+  - {}
+  - {}
+b:
+  - {}
+c:
+  - foo: 'foo'
+    bar: 'bar'